The answer is arc, its one the 12 principles of animation :)
        
             
        
        
        
Answer:
try a rose with thorns and leaves and add some crass around the roses thats a good one 
Explanation:
 
        
             
        
        
        
Answer:
Press on the Pens a little bit when you go downwards. But lift it up again once you start moving the pencil upwards. This way the stroke will move gradually from thick to thin.